1. Field of the Invention
The present invention relates to an optical waveguide module which is used in an optical fiber communication network and others.
2. Related Background Art
An optical waveguide module comprising, e.g., an optical branching filter and others, generally comprises a module unit which is formed by bonding end faces of optical fiber cables with a respective end face of an optical waveguide and which is housed in a housing. In the optical waveguide module, under the high temperature and high humidity, an adhesive which is used in the connecting portion between the optical waveguide and the optical fibers moistens and is degraded, which causes the degradation of characteristics: increase of loss and light reflection, degrade of tensile strength.
Therefore, the housing is sealed with, e.g., a nitrogen gas (N.sub.2). Alternatively, the housing is filled with a jelly-like resin. As such conventional techniques, for example, a technique disclosed in "Japanese Patent Laid-Open No. HEI 5-27139 (27139/1993)" is known. As a technique of coating the outside of the housing with a resin, for example, a technique disclosed in "Japanese Patent Laid-Open No. HEI 5-45531 (45531/1993)" is known.